1. Field of the Invention
The present invention relates to an improvement in a hood assembly of a vehicle and, more particularly, to an improvement in positioning and arrangement of an actuator for lifting up a hood.
2. Description of the Related Art
It has heretofore been proposed to provide a vehicular hood assembly for lifting up a rear end of a hood and retaining the hood at a lifted height when a running vehicle collides with an object to be protected (protective object), as is known from, for example, Japanese Patent Laid-Open Publication NO. HEI-9-315266.
The known hood assembly includes a protective object collision sensor which detects collision of a running vehicle against the protective object to thereby produce a detection signal. The detection signal is then supplied to a control unit which generates a command signal to operate an actuator of a hood lift-retaining mechanism for lifting up the hood, which is consequently retained at its lifted position. A hook, which is pivotally supported with a rod of the actuator by means of a retainer pin, is urged such that a part of the hook protrudes from the rod by the action of a compression spring located in the rod.
When the actuator is operated to raise the rod for thereby lifting up the hood, the hook is forced to protrude by the action of the compression spring to be brought into engagement with a vehicle body, thereby avoiding lowering movement of the rod to retain the hood at its lifted position.
However, in order to avoid the rod from being lowered, the actuator is constructed of the hook, the retainer pin and the compression spring, with a resultant increase in the number of component parts to render the structure to be complicated Further, the assembling work for these small-sized component parts such as the hook, the retainer pin and the compression spring needs a troublesome skilled practice, thus deteriorating assembling efficiency of the actuator.
In addition, provision of the actuator located at the rear end of the hood makes the use of the actuator to be limited to a particular type which has a given lifting force. For this reason, it is necessary to prepare individual actuators of various types is which provide lifting forces independent from each other so as to meet the hoods of the respective vehicles of various models. Also, it is required to prepare the actuator which has an increased lifting force depending on the position in which the hinge mechanism is located for opening or closing the hood, with a resultant increase in size of the actuator with difficulty encountered in miniaturization and weight reduction of the actuator.
It is therefore an object of the present invention to provide an actuator for a hood assembly of a vehicle, which has a reduced number of component parts to enable easy assemblage of the same.
Another object of the present invention is to provide a hood assembly of a vehicle, which is capable of effecting miniaturization of an actuator while enabling an actuator of a single kind to be provided which can be commonly applied to hoods of various kinds different in models of the vehicles.
According to an aspect of the present invention, there is provided a hood assembly for a vehicle, which comprises a vehicular hood, and at least one actuator for lifting up a rear end of the vehicular hood to a given height when the vehicle collides with a protective object. The actuator includes a rod having a part with lower rigidity than that of the other part of the rod. The rod is bendable at the lower rigidity part when the rod is raised to lift up the hood.
Preferably, the lower rigidity part is comprised of a constricted portion having a smaller diameter than that of the is other part of the rod.
When the vehicle collides with the protective object, the actuator is operated to raise its rod for lifting up the hood by a given height. Then, the protective object encounters a secondary collision with the hood, an impact load exerted to the protective object and the hood itself is concentrated to the rod, which is consequently bent at its constricted portion, which has the lower rigidity part, without returning to its original position. Use of a bending mechanism of the rod allows the hood to be retained at its lifted position. Accordingly, it is unnecessary to specially provide an independent rod retaining mechanism through the use of the aforementioned bending mechanism of the rod, with a resultant reduction in the number of component parts while enabling the actuator to be assembled at an improved assembling work efficiency.
Desirably, the actuator is provided at an arbitrary position rearward of the center of gravity of the hood in a longitudinal direction of the vehicle. More particularly, the actuator is located in an area rearward of the center of gravity of the hood at a suitable position near the rear end of the hood or near the center of gravity of the hood depending on the kinds of the hoods. Accordingly, the actuator of a single kind can be commonly applied to the hoods of various types different in shape and/or weight. For example, in a case where the hood has a heavy weight, the actuator may be located at a position near the rear end of the hood. In a case where the hood has a light weight, the actuator may be located at another position rearward of the Center of gravity of the hood in close proximity thereto. That is, even with the provision of the actuator of a single kind, i.e., with a type which provides a constant lifting force, the actuator may be located at a selected position to meet the hoods of various kinds which differ in weight and shape for thereby rendering the actuator to be commonly applied to the hoods of the various types.